PLEASE NOTE: it absolutely has to be chntpw 0.99.5. Newer version are somehow incompatible with Windows SAM

I suggest you download the i386 versions of both Ubuntu and chntpw - just in case you need to unlock an account on mom's 8-year-old PC.Also, that's what I've tested. I *think* amd64 versions have some incompatibility, but feel free to test for yourselves.

Preparation:

1. Format the USB drive. FAT32.2. Use Unetbootin to put the Ubuntu .ISO on the USB drive. It'll take a few minutes.3. When Unetbootin is done, use your favourite file explorer to copy the chntpw_0.99.5-0+nmu1_i386.deb on the USB drive's base dir.

Execution:

4. Boot up the target PC using your USB drive into Ubuntu. Click on "Try Ubuntu".5. Open Terminal6. Install chntpw:sudo dpkg -i /cdrom/chntpw*7. Open the file explorer and click on the Win 7 drive (easiest way to mount it). The disk is mounted in /media/SomeRandomDiskID, where SomeRandomDiskID will be some huge mostly-numbers name.8. In terminal:cd /media/SomeRandomDiskID/Windows/System32/config9. Start the interactive mode of chntpw:sudo chntpw -i SAM10. Press "1" to edit user data and passwords.11. Follow the prompt to reset passwords or unlock the hidden administrator account. Just remember to save the changes on your way out.11. Done. Shutdown the PC, remove the USB. Reboot.

If you get stuck when trying to mount the drive and you get some error message about "bad NTFS partition size":In terminal: Run fdisk -l Find which partition is the Win7 partition (e.g. /dev/sdb1) Run fixntfs /dev/sdb1 Try again to mount the disk.